Most importantly, don't give the person a reason to decline your message.

"Essentially, find a way to not be declined," Pham said. "So that means asking if you could have a five minute phone call or a fifteen minute tea. Say you think that the initiatives that they're working on are so incredible and interesting that you'd love to support them in any way possible."

She said her own networking paid off.

"I just spent so much time learning from as many people as possible, people that I admired in the industry that I was focused on," she said. "I really reached out to those people that I admired."

Ultimately, some of those connections became valuable partnerships. Today, Mogul's board is made up of the president of BBC Worldwide North American, the former chairman and president of Hearst Magazines, and the co-founder of Match.com, among others Pham cold emailed.

But Pham added it's important to not get discouraged if your cold email campaign isn't successful straight away.

"Along the way, you may not get replies," she said. "You may get some 'nos.' Just know that those 'nos' are 'not right nows.' They probably won't even remember your name if you reach out two months later or a year later. It's always worth it to reach out. What's the worst that can happen?"